Re: [Qemu-devel] [PATCH] Fix non-ACPI Timer Interrupt Routing

[Beth Kon <eak@us.ibm.com>]

Sebastian Herbszt wrote:
> Beth Kon wrote:
>> This is part of a bigger change for QEMU, incorporating irq0->inti2 
>> override for ACPI, and non-ACPI, driven by addition of the HPET. It 
>> required BIOS changes as well as QEMU changes to route irq0 to inti2 
>> of the IOAPIC. This patch alone is not complete. I have tested the 
>> complete solution in QEMU, thus the guards.
>
> I just tested qemu r7185 with bochs bios (without your patch) and used 
> a Linux
Do you mean you used a bochs bios that doesn't include #ifdef BX_QEMU 
portions? Then it wouldn't work because QEMU overrides irq0->inti2 in 
its ioapic code and without the matching bios that notifies the guest of 
the override, boots would likely fail. This change was put in because of 
the needs of the HPET, but now it is standard procedure for QEMU. With 
or without HPET, QEMU will override irq0->inti2.

If you mean that you used a QEMU Bochs (with ifdef BX_QEMU included), 
please let me know what kind of errors you are seeing.

> 2.6.27.7 guest (openSUSE-11.1-NET-i586.iso). If i don't misunderstand you
> this change is only needed with HPET. I have tested the following 
> configurations
> which all fail:
>
> hpet enabled, no guest kernel parameters
> hpet enabled, guest kernel with acpi=off
> hpet disabled, no guest kernel parameters
> hpet disabled, guest kernel with acpi=off
>
> Since it even fails with HPET disabled, this change can't only be 
> needed for HPET, can it?
>
> Ed: Have you tried your Linux guest with HPET enabled or disabled in 
> your original report / patch?
>
> - Sebastian
>
>
>